I need a create a query to get all attendance of the an employee within a time limit. But the time is from different table. I need to create a query like the one below, but I dont know how?
SELECT * FROM attendance WHERE employeeid = 25 AND attendance_date BETWEEN (SELECT bill_fromdate,bill_todate FROM bill WHERE bill_id = 21487)
I am using PostgreSQL 8.4.
You could use a join instead of a subquery:
SELECT *
FROM attendance a
JOIN bill b ON
a.attendance_date BETWEEN b.bill_fromdate AND b.bill_todate
WHERE a.employeeid = 25 AND AND b.bill_id = 21487
Either use a JOIN (as in Mureinik's answer) or use a sub-select with an exists condition:
SELECT a.*
FROM attendance a
WHERE a.employeeid = 25
AND exists (select 1
from bill b
where b.bill_id = 21487
and a.attendance_date BETWEEN b.bill_fromdate AND b.bill_todate)
Given your example query, most probably there isn't a difference between using the join or the sub-select.
But they have different meanings and a join could return a different result (i.e. more rows) than the sub-select (but again I doubt it in this situation).
Related
I'm writing a query to multiply the count that I receive from subquery to fees amount, But I don't know how to do that. Any help/suggestion?
Oracle query is:
select courseid,coursename,fees*tmp
from course c join registration r on
r.courseid=c.courseid
and tmp IN (select count(*)
from course c join registration r on
r.courseid=c.courseid group by coursename);
I tried to use like a variable tmp ,But i don't think it works in oracle query. Is there an alternative way to do so?
You can't do that, because you can only select data from tables that appeared between FROM and WHERE. The IN operator is a quick way to save having to write a bunch of OR statements, it is not something that can establish a variable in the outer query.
Instead do something like:
select courseid,coursename,fees * COUNT(r.courseID) OVER(PARTITION BY c.coursename)
from course c join registration r on
r.courseid=c.courseid
Edit/update: you noted that this query produces too many rows and you only want to see distinct course names. In that case it would be better to just use the registrations table to count the number of people on the course and then multiply the fees:
SELECT
c.courseid, c.coursename, c.fees * COALESCE(r.numberOfstudents, 0) as courseWorth
FROM
course c
LEFT OUTER JOIN
(select courseid, COUNT(*) as numberofstudents FROM registration GROUP BY courseid) r
ON c.courseID = r.courseid
You can use a windowing function like Caius or you can use a join like this:
select courseid,coursename, fees * COALESCE(sub.cnt,0)
from course c
join registration r on r.courseid=c.courseid
left join (
select coursename, count(*) as cnt
from course c2
join registration r2 on r2.courseid=c2.courseid
group by coursename
) as sub;
note: I make no claim your joins are correct -- I'm basing this query off of your example not on any knowledge of your data model.
I have the following query:
SELECT top 2500 *
FROM table a
LEFT JOIN table b
ON a.employee_id = b.employee_id
WHERE left(a.employee_rc,6) IN
(
SELECT employeeID, access
FROM accesslist
WHERE employeeID = '#client.id#'
)
The sub select in the where clause can return one or several access values, ex:
js1234 BLKHSA
js1234 HDF48R7
js1234 BLN6
In the primary where clause I need to be able to change the integer expression from 6 to 5 or 4 or 7 depending on what the length of the values returned in the sub select. I am at a loss if this is the right way to go about it. I have tried using OR statements but it really slows down the query.
Try using exists instead:
SELECT top 2500 *
FROM table a LEFT JOIN
table b
ON a.employee_id = b.employee_id
WHERE EXISTS (Select 1
FROM accesslist
WHERE employeeID = '#client.id#' and
a.employee_rc like concat(employeeID, '%')
) ;
I don't see how your original query worked. The subquery is returning two columns and that normally isn't allowed in SQL for an in.
Move the subquery to a JOIN:
SELECT TOP 2500 *
FROM table a
LEFT JOIN table b ON a.employee_id = b.employee_id
LEFT JOIN accesslist al ON al.access LIKE concat('%', a.employee_id)
WHERE al.employeeID = '#client.id#'
Like Gordon, I don't quite see how your query worked, so I'm not quite sure if it should be access or employeeID which is matched.
This construct will enable you to do what you said you want to do, have an integer value depend on somethign from a subquery. It's the general idea only, the details are up to you.
select field1, field2
, case when subqueryField1 = 'fred' then 1
when subqueryField1 = 'barney' then 2
else 3 end integerValue
from table1 t1 join (
select idField subqueryField1, etc
from whereever ) t2 on t1.idFeld = t2.idField
where whatever
Also, a couple of things in your query are questionable. First, a top n query without an order by clause doesn't tell the database what records to return. Second, 2500 rows is a lot of data to return to ColdFusion. Are you sure you need it all? Third, selecting * instead of just the fields you need slows down performance. If you think you need every field, think again. Since the employee ids will always match, you don't need both of them.
I have 2 database tables:
customers and customers_1
I have 100 customers in the customers table but only 99 customers in the customers_1 table. I would like to write a query that will compare the 2 tables and will result in the missing row.
I have tried this following SQL:
select * from customers c where in (select * from customers_1)
But this will only check for the one table.
Your query shouldn't work this way. You have to compare one column to another and use NOT IN instead of IN:
select *
from customers c
where customerid not in (select customerid from customers_1)
However, Since you are on SQL Server 2008, you can use EXCEPT:
SELECT * FROM customers
EXCEPT
SELECT * FROM customers_1;
This will give you the rows which are in the customers table that are not in customers_1 table:
EXCEPT returns any distinct values from the left query that are not
also found on the right query.
This is easy. Just join them with a left outer join and check for NULL in the table which has the 99 rows. It will look something like this.
SELECT * FROM customers c
LEFT JOIN customers1 c1 ON c.some_key = c1.some_key
WHERE c1.some_key IS NULL
Instead of NOT IN clause consider using NOT EXISTS. NOT EXISTS clause performs better in this particular scenario. Your query would look like:
SELECT * FROM Customer c WHERE NOT EXISTS (SELECT 1 FROM Customer_1 c1 WHERE c.Customer_Id = c1.Customer_Id)
SELECT 1 is just for readability so everyone will know that I don't care about the actual data.
I have a statement like this:
select lastname,firstname,email,floorid
from employee
where locationid=1
and (statusid=1 or statusid=3)
order by floorid,lastname,firstname,email
The problem is the column floorid. The result of this query is showing the id of the floors.
There is this table called floor (has like 30 rows), which has columns id and floornumber. The floorid (in above statement) values match the id of the table floor.
I want the above query to switch the floorid values into the associated values of the floornumber column in the floor table.
Can anyone show me how to do this please?
I am using Microsoft sql server 2008 r2.
I am new to sql and I need a clear and understandable method if possible.
select lastname,
firstname,
email,
floor.floornumber
from employee
inner join floor on floor.id = employee.floorid
where locationid = 1
and (statusid = 1 or statusid = 3)
order by floorid, lastname, firstname, email
You have to do a simple join where you check, if the floorid matches the id of your floor table. Then you use the floornumber of the table floor.
select a.lastname,a.firstname,a.email,b.floornumber
from employee a
join floor b on a.floorid = b.id
where a.locationid=1 and (a.statusid=1 or a.statusid=3)
order by a.floorid,a.lastname,a.firstname,a.email
You need to use a join.
This will join the two tables on a certain field.
This way you can SELECTcolumns from more than one table at the time.
When you join two tables you have to specify on which column you want to join them.
In your example, you'd have to do this:
from employee join floor on employee.floorid = floor.id
Since you are new to SQL you must know a few things. With the other enaswers you have on this question, people use aliases instead of repeating the table name.
from employee a join floor b
means that from now on the table employee will be known as a and the table floor as b. This is really usefull when you have a lot of joins to do.
Now let's say both table have a column name. In your select you have to say from which table you want to pick the column name. If you only write this
SELECT name from Employee a join floor b on a.id = b.id
the compiler won't understand from which table you want to get the column name. You would have to specify it like this :
SELECT Employee.name from Employee a join floor b on a.id = b.id or if you prefer with aliases :
SELECT a.name from Employee a join floor b on a.id = b.id
Finally there are many type of joins.
Inner join ( what you are using because simply typing Join will refer to an inner join.
Left outer join
Right outer join
Self join
...
To should refer to this article about joins to know how to use them correctly.
Hope this helps.
I'm struggling to compile a query for the following and wonder if anyone can please help (I'm a SQL newbie).
I have two tables:
(1) student_details, which contains the columns: student_id (PK), firstname, surname (and others, but not relevant to this query)
(2) membership_fee_payments, which contains details of monthly membership payments for each student and contains the columns: membership_fee_payments_id (PK), student_id (FK), payment_month, payment_year, amount_paid
I need to create the following query:
which students have not paid fees for March 2012?
The query could be for any month/year, March is just an example. I want to return in the query firstname, surname from student_details.
I can query successfully who has paid for a certain month and year, but I can't work out how to query who has not paid!
Here is my query for finding out who has paid:
SELECT student_details.firstname, student_details.surname,
FROM student_details
INNER JOIN membership_fee_payments
ON student_details.student_id = membership_fee_payments.student_id
WHERE membership_fee_payments.payment_month = "March"
AND membership_fee_payments.payment_year = "2012"
ORDER BY student_details.firstname
I have tried a left join and left outer join but get the same result. I think perhaps I need to use NOT EXISTS or IS NULL but I haven't had much luck writing the right query yet.
Any help much appreciated.
I'm partial to using WHERE NOT EXISTS Typically that would look something like this
SELECT D.firstname, D.surname
FROM student_details D
WHERE NOT EXISTS (SELECT * FROM membership_fee_payments P
WHERE P.student_id = D.student_id
AND P.payment_year = '2012'
AND P.payment_month = 'March'
)
This is know an a correlated subquery as it contains references to the outer query. This allows you to include your join criteria in the subquery without necessarily writing a JOIN. Also, most RDBMS query optimizers will implement this as a SEMI JOIN which does not typically do as much 'work' as a complete join.
You could use a left join. When the payment is missing, all the columns in the left join table will be null:
SELECT student_details.firstname, student_details.surname,
FROM student_details
LEFT JOIN membership_fee_payments
ON student_details.student_id = membership_fee_payments.student_id
AND membership_fee_payments.payment_month = "March"
AND membership_fee_payments.payment_year = "2012"
WHERE membership_fee_payments.student_id is null
ORDER BY student_details.firstname
You can also write following query. This will gives your expected output.
SELECT student_details.firstname,
student_details.surname,
FROM student_details
Where
student_details.student_id Not in
(SELECT membership_fee_payments.student_id
from membership_fee_payments
WHERE
membership_fee_payments.payment_year = '2012'
AND membership_fee_payments.payment_month = 'March'
)